function rollover(name){
	var topimage = new Image();
	topimage.src = "image/btn-" + name + "-top-on.jpg";
	
	document.images[name].src = topimage.src;
	document.getElementById(name).style.backgroundPosition = "0 -85px";

}

function rollout(name){
	var topimage = new Image();
	topimage.src = "image/btn-" + name + "-top.jpg";
	
	document.images[name].src = topimage.src;
	document.getElementById(name).style.backgroundPosition = "0 30px";

}